Drawing instrument.



PATENTED AUG. 27, 1907.

DRAWING INSTRUMENT. APPLICATION FILED OOT.31,

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DRAWING INSTRUMENT. APPLICATION FILED O0T.31.1906.

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PATENTED AUG. 27,. 1907.

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No. 864,455. PATENTED AUG. 27, 1907.

J. DEGEN.

DRAWING INSTRUMENT. APPLICATION FILED OCT. 31, 1906.

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No. 864,455 PATENTBD AUG. 27, 1907. LDEGEN.

DRAWING INSTRUMENT. APPLICATION FILED 0OT.31,1906.

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WITNESSES HVVENTO/i ATTORNEYS.

JULIUS DEGEN, OF TRENTON, NEW JERSEY.

DRAWING INSTRUMENT.

Specification of Letters Patent.

. Patented Aug. 27, 1907.

Application filed October 31, 1906. Serial No. 341,454,

To all whom it may concern:

Be it known that I, J ULIUS' Dnenn, of Trenton, in the county of Mercer,and in the State of New Jersey, have invented a certain new and usefulImprovement in a Drawing Instrument; and do hereby declare that thefollowing is a full, clear, and exact description thereof, referencebeing had to the accompanying drawings, in which- Figure 1 is ahorizontal sectional view, taken in the plane of the upper rack guide,of the parts directly connectcd with the pen holder of an ellipsographembodying my invention; Fig. 2 is a horizontal sectional view takenbetween the guiding plates for the pen holder of the parts immediatelyabout the pen holder in Fig. 1; Fig. 3 is a plan view of the completeellipsograph embodying my invention. Fig. 4 is a plan view of astructure embodying my invention in drawing a hyperbola. Fig. 5 is aplan view of that form of our instrument illustrated in Figs. 1 and 4,showing springs in the rack guides; Fig. 6 is a side elevation of Fig.5; Fig 7 is an enlarged view, partly in section, of the parts above atthe pen holder; Fig. 8 is a view, partly in section, of the racks andrack-guides shown in Fig. 7, the view being taken in a plane at rightangles to Fig. 7; Fig. 9 is an en larged view, partly in section, of oneof the posts and attached parts; Fig. 10 is a plan view, partly insection,

of the pin-holding parts at the foot of Fig. 9; Fig. 11 is a plan view,partly in section of a rack,-rack-guide and pinion.

The object of my invention has been to provide an instrument which isadapted for drawing either an ellipse or hyperbola, and to such ends myinvention consists in the drawing instrument hereinafter specified.

My instrument is based on the principle that the sum or the differencerespectively of the distances from any point of an ellipse or ahyperbola to the foci of such curve is constant.

In carrying my invention into practice I provide posts 1 and 2 havingpoints 3 and 4 respectively which are adapted to be stuck into the paperat the foci. Forked arms 5 and 6 are pivoted by means of pivots 7 and 8to the said posts, and such arms are provided with pins 9 and 10respectively, which can be stuck into the paper to prevent rotation ofthe posts 1 and 2. Each post 1 and 2 has swiveled upon it a sleeve 11 or12, and at the upper end of the sleeve the post extends through it,having secured to it a pinion 13 or 14, each sleeve having a guide-way15 having a rack guided therein and preferably having a spring 16secured in the guide way to hold the rack against the pinion. A rack 17occupies the guide-way of the sleeve 11 and engages the pinion 13, and arack 18 occupies the guide-way of the sleeve 12 and engages the pinion14. The rack 18 extends through a slide-way 19 formed in a block 20, andsuch block has a bore 21 which is adapted to receive the lower end of astud 22, having on it upper and lower pinions 23 and 24. A spring 25 isprovided in the slideway to hold the rack 18 against the pinion 24. Anup per block 26, exactly the reverse of the block 20, is provided, andthe rack 17 occupies the slide-way of such block, the upper end of thestud 22 having a bearing in the bore 27 of such upper block. The blocks20 and 26 respectively have an upper and lower conical seat 28 and 29which seats are engaged by the conical points or screws 30 and 31carried by a yoke 32 which has upon its .lower end a pen or pencil 33,and upon its upper end a thumb-piece 34. In order to insure that the penshall always be turned parallel to the curve to be drawn, a plate 35 isswiveled on a sleeve 36 through which passes the stud 22 carrying thetwo pinions, and such plate has a slot 37 that is engaged by a roller38, the said roller being mounted upon or formed in one piece with astud 39 that engages cam slots 40 and 41, which are respectively formedin the blocks 20 and 26. "The plate 35 has a notch 42 or other formationby which it engages the yoke 32. i

. In the useof my instrument for drawing an ellipse, as illustrated inFigs. 1, 2, and 3, the points are set in the foci and the racks areswung to the full line position in Fig. 3. The racks are pressed backout of engagement with their respective pinions, this being permitted bythe springs in the slide-way, and the racks are slid along until thedistance from the pen to the nearest focus plus half the distancebetween the foci is'equal to half the lengthof the ellipse desired. The

pen is then simply caused to travel around the curve. As the racks l7and 18 engage opposite sides of their respective pinions, any change inthe length of the effective portion of one rack is exactlycounter-balanced by an equal but opposite change in the effectivelength.

of the opposite rack, so that the sum of the distances from the pen tothe foci remains constant and a perfect ellipse results.

When using my instrument to drawan hyperbola, as illustrated in Fig. 4,the points 3 and 4 are stuck in the paper at the foci, and the pen isplaced between the foci, the racks being adjusted so that the distanceof the pen to the nearest focus shall be correct, and the pen is thencaused to travel along the curve. In this case, as with the ellipse, anychange in the effective length of one rack is followed by an equalchange in the length of the opposite rack, so that the difference of theeffective lengths of the racks between the pen and the foci remainsconstant. In either case the plate 35 is caused by the roller 38 andstud 39 to hold the pen half way between the two racks, which causes thepen to always be in line with the curve to be drawn.

It is obvious that various changes can be made in the above illustratedconstruction which will embody the principles of my invention in variousforms without departure from the spirit of it. For instance, instead ofthe posts 2 being prevented from revolving and haying pinions thatengage their respective racks, the said posts may be directly secured tothe racks as illus trated in Figs. 12 and 13. In this case the posts 42and 43 are simply placed at the foci, and the racks 44 and 45 adjustedin the slides at the pen-holder. If the pinions 23 and 24 are in thisinstance of sufilciently small diameter, the ellipse drawn Will bepractically, although not theoretically, perfect. The construction inFigs. 12 and 13 is identical with that illustrated in the precedingfigures, except that the posts 42 and 43 are directly connected with theracks 44 and 45.

Having thus described my invention, 1 claim:

1. In a drawing instrument, the combination of two posts adapted to beerected at the foci of a conic section, pinions secured tosaid posts, apen holder having a rotatable part, teeth mounted on said part,rack-guides mounted on the pen holder, and racks connecting said pen.holder with the pinions on said posts, whereby the sum or thedifference of the distances from said pen to said foci shall remainconstant.

2. In a drawing instrument, the combination of posts having teeth andrack guides thereon, said posts being adapted to be set up at the fociof a conic section to be drawn, a pen-holder having a rotatable parthaving teeth thereon, racks for engaging said teeth, and guides formaintaining said racks in engagement with said teeth, said guidespermitting said racks to be detached from said teeth, whereby theinstrument may be readily adjusted.

3. In a drawing instrument, the combination of two posts adapted to beset up at the foci of a conic section, pinions secured to said posts, apen-holder also having a rotatable part having teeth; racks, rack-guidesswiveled on said posts and said pen-holder respectively, and yieldingmeans in said rack-guides permitting the disengagement of said racks andsaid pinions or teeth.

4. In a drawing instrument, the combination of two posts adapted to beset up at the foci of a conic section, pinions securedto said posts, apen-holder also having a rotatable part having teeth, racks, rack-guidesswiveled on said posts and said pen-holder respectively, and a spring insaid rackguides permitting the disengagement of said racks and saidpinions or teeth.

5. In a drawing instrument, the combination of posts adapted to be setup at the foci of a conic section, pinions on Said posts, a pen-holderhaving a rotatable part having teeth, racks adapted to engage saidpen-holder and said pinions and teeth, rack-guides on said posts and onsaid pen-holder, and means for keeping said pen-holder midway betweenthe vertical planes of said racks.

G. In a drawing instrument, the combination of two posts having pinionsthereon, a pen-holder having rotatable means for engaging racks,raclcguides swiveled to said posts and to said pen-holder, racks mountedin said guides, said rack-guides on said pen-holder having overlappingportions that are provided with oppositely arranged spiral guide-ways,and a projection on the pen-holder adapted to engage said guideways.

7. In a drawing instrument, the combination of posts having rotatablepinions thereon, a pen-holder having means for engaging racks,rack-guides swiveled on said posts and on said pen-holder, racks mountedin said guides, said rack guides on said penholder having overlappingportions that are provided with oppositely arranged spiral guide-ways, aplate mounted between said over-lapping portions and engaging thepen-holder, a pin engaging said spiral guide-ways and a slot in saidplate.

8. In a drawing instrument, the combination of posts having pinionsthereon, a stud having pinions thereon, rack-guides swiveled on saidposts and on said stud, racks engaging said guides, said rack-guides onsaid studs having overlapping portions that are provided with oppositelyarranged spiral guide-ways, a plate mounted between said overlappingportions, a pin engaging said guide-ways and a slot in said plate, ayoke embracing the upper and lower sides of the rack guide-ways on saidstud, said yoke being engaged by said plate, and the pen carried by saidyoke.

9. In a drawing instrument, the combination of points adapted to bestuck in the paper, racks connected to said points, a pen or pencilholder, and a rotatable part having teeth and rack-guides carried bysaid holder.

10. In a drawing instrument, the combination of points adapted to bestuck in the paper, racks connected to said points, guides "for saidracks, said guides being swiveled together, a rotatable part havingteeth engaging said racks in said guides, and a pen secured to saidguides. I

11. In a 'drawing instrument, the combination of points adapted to bestuck in the paper at the foci of a conic section, racks swinging aboutsuch points, apen or penholder, and teeth and racleguides on said holderengaging said racks.

12. In a drawing instrument, the combination of two stationary pinionsfixed above the foci of a conic section, a pen having a pinion securedthereon, racks connecting said pen with said stationary pinions, guidesconnected to said pinions and engaging said racks whereby the pen iscaused to travel along said conic section.

13. In a drawing instrument, the combination of two stationary pinionsfixed above the foci of a conic section, guides swiveled on thesepinions, a pen having a pinion secured thereon, two guides swiveled onthis pinion, and racks connecting said pinion, and guides on the penwith said stationary pinions and guides, whereby the pen is caused totravel along said conic section.

14. In a drawing instrument, the combination of a pen, two guidesthereon rotatable around a common axis, a pinion in said guidesrotatable around the same axis, racks in said guides engaging saidpinion, independent guides shiftable on said racks, pinions carried bysaid independent guides and engaging said racks, and means to fix saidpinions above the foci of the conic section to be drawnv 15. In adrawing instrument, the combination of two posts adapted to be erectedat the foci of a conic section,

bars connected with said posts, a pen-holder carried by said bars at apoint of intersection thereof, and means engaging said bars formaintaining a point on said penholder midway between the vertical planesof said bars.

In testimony that I claim the foregoing I have hereunto set my hand.

JULIUS DEGEN.

Witnesses:

.TouN R. D. Bownn, HARRY A. HANNUM.

